trying to Understand cyl head flow #'s

HI guys!

I was wondering if someone could help me understand how to translate cylinder head flow numbers and how they correlate to making hp. For example. The G head is listed as flowing 160cfm at .500 lift. I found a formula that states:

airflow x 0.257 x number of cylinders= attainable hp

in this case.

160 x .257 x 4=164.48hp.

in NA form i can understand that this is a 164hp head, but, how do you relate the CFM rating of a head to the power output for a turbo? Putting it another way, how do i relate the flow ratings of a turbo to the flow rating of a cylinder head, to help me understand which is better for making power and how much power it can make?

For instance, at 12psi on a 2.2 liter motor with a 100% VE at 5500rpm, the motor is ingesting 395cfm. how does the 160 cfm rating of a G head tell me if its a good match or not and how much power it will make over [for arguments sake] a swirl which is said to run 20cfm less?

When i read a compressor map, do i add the flow rating of the turbo to the flow rating of the cylinder head to get how many CFM's the motor will be ingesting at a given VE and Rpm?

Lastly, how do i go about calculating what a head will need to flow in order to have it spin at a given rpm? i figured out that the cylinder volume of a 2.2 is around 33 Ci or 0.54 liters. how do i go about figuring out the flow needed to run a 2.2 say for example at 7000 rpm? How many CFM over say 160cfm at .500 lift of a G head would i need to get this goal[7000rpm]?

I hope i have made sense with my question.
I do appreciate your help!
bernie